A robust host-guest interaction controlled probe immobilization strategy for the ultrasensitive detection of HBV DNA using hollow HP5–Au/CoS nanobox as biosensing platform

The combination of supramolecular chemistry and nanotechnology has potentially applied in the construction of biosensors, and thus improves the analytical performance and robustness of electron devices. Herein, a new sandwich-type DNA sensor was constructed for ultrasensitive determination of hepatitis B virus (HBV) DNA, a recognized marker for chronic hepatitis B. The water-soluble pillar[5]arene stabilized Pd NPs combined with reduced graphene oxide nanosheet (WP5–Pd/RGO) was synthesized and employed as supporting material for the modification of electrode surface. The probe DNA was immobilized onto the electrode surface through a new strategy based on the host-guest interaction between WP5 and methylene blue labeled DNA (MB-DNA). Moreover, MOF-derived cobalt sulfide nanobox was prepared to anchor the hydroxylatopillar[5]arene stabilized Au NPs (HP5–Au/CoS), which had superior electrocatalytic performance towards H2O2 reduction to achieve signal amplification. Under the optimized conditions, the proposed sensor displayed a linear relationship between amperometric currents and the logarithm of tDNA solution from 1 × 10−15 mol/L to 1 × 10−9 mol/L, and a low detection limit of 0.32 fmol/L. What's more, the DNA sensor had remarkable behaviors of stability, reproducibility, specificity, and accuracy, which provided a potential and promising prospect for clinical diagnosis and analysis.